Domestic appliance



Jan. 4, 1944; D, K. FERRIS DOMESTIC APPLIANCE Filed Jan. 50, 1941 2 Sheets-Sheet 1 Jan. 4-, 1944. E s 2,338,236

DOMESTIC APPLIANCE 2 Sheets-Sheet 2 Filed Jan. 30, 1941 A as W A 9 "4 7 W W y W Patented Jan. 4, 1944 UNITED STATES PATENT orr ca DOMESTIC APPLIANCE Donald K. Ferris, Dayton, Ohio, assignor to Gen- I eral Motors Corporation, Dayton, Ohio, a corporation of Delaware Application January 30, 1941, Serial No. 376,674

for heating utensils.

are provided with resistanceelements receiving Claims. (Cl. 219-37) This invention relates to domestic appliances and more particularly to electric ranges.

, An object of this invention is to provide a heating unit for-electric ranges which utilizes induced currents for heating purposes, and in which the heating value of these currents may be modified to provide varying degrees of heat.

Another object of my invention isto provide a heating unit for a range, or the like, having gradually differing heat selections.

. varied gradually to provide a selection of gradu- Fig. 1' is a view, in perspective," of an electric range utilizing my invention;

Fig. 2 is a top view, partly in section, of a heating unit embodying features of my invention, the view taken along the line 2--2.of Fig. 3;.

Fig. 3 is a vertical cross-section of the unit shown in Fig. 2, the section being taken along the line 33 of Fig. 2, the windings i5 and 16 being shown diagrammatically;

Fig. 4 is an enlarged cross-section of a portion of Fig. 3;

Fig. 5 is a view showing portions of the magnetic core;

' Fig. 6 is a top view of a portion of Fig. 4 with the rings I1 and I8 removed;

Fig. 7 is a cross-section taken along the line 'l'| of Fig. 4, the section following the curve of rings 11 and I8; and V Fig. 8 is a diagrammatic wiring diagram for one heating unit. v

The usual range is provided with top units Ordinarily the top units current directly from the power lines. While it has been possible to select several degrees of heating value in such .top units, there has always been a decided jump between values, with the ally varying degrees of heat.

To this end, alternating current from the usual supply lines is supplied to switches i2 from which its flow may be manually controlled to the respective units H on the top of the range. A unit Ii may include one or more magnetic cores l3 and i4, having primary windings l5 and it having a relatively large number of turns under the control of a switch [2. The cores l3 and it preferably are U-shaped to receive" a ring ll. The ring Il may be formed integrally with a top ring l8, which'forms the top of the heating unit and extends adacent to the metal cooking top is of the range ill.

The ring I! has been shown as applied to a top ring it, separate from the cooking utensil. However, the ring Il may be cast, or may be secured to, the bottom of a cooking utensil, so

that the heat produced in the ring l'l may be conducted directly tothe contents of the cooking utensil.

Adustment of the heat produced within the ring ll may be secured by providing certain portions of the ring ll with diiferent induced current capacity. In addition, the top unit may be provided with a handle .2! for moving the unit about its vertical central axis thereof, so as to place different parts of the'ring ll across the magnetic fields of the cores l3 and M. In this manner the ring ll may be so placed that portions of the ring having, a capacity of relatively great induced current are placed across the magnetic field or the ring ll may be turned so that portions of the ring having a less capacity for induced currents are across the magnetic field. In this manner the intensity of the heat produced within the ring I! may be gradually varied.

If the ring i1 is made integral with a cooking utensil, the utensil may be turned about its verresult that one heating value may be too great and the next heating value too small for a particular need. The units embodying my invention are capable of producing heat in gradually varying degrees of heat, so that any desired heat output may be selected. In my invention the range III is provided with top units ll located at the usual cooking top of the range and supplied by induced currents derived from altertical axis so as to placediiierent parts of its ring I! across the magnetic fields in. the same manner that the ring 18 is so changed. If desired, the cooking utensil may be provided with a handle for liftingit, and this handle may be used'for turning the vessel to the desired place.

, When cooking utensils are to be provided with their individual heating rings, the range top may be marked to inidicate the place over which the handle is to be located in order to obtain the nating current of constant .voltage from the,

usual. supply lines. The construction is such that the amount of induced currents may be desired degree of heat, For example, the words "high" and low may be placed on the stove to indicate where the handle 2| is to be located Figs. 4 and 5. The preferably made of iron laminations of the shape ,This -,tobe

as implying perfect circles.

the advantages of my invention come within the or to'indicate where located.

Details of the construction of the ring I! and the heating magnets are shown more clearly in heating magnet cores are shown in Fig. 5. One set of laminations is L- shaped as indicated at 30 while the other set of laminations may berectangular' as indicated at 3|. The magnetic core is made of two L-shaped sections of laminations. Each section is made by assembling alternate laminations 30 and 3| with the laminations 3| placed between the vertical portions of laminations 30. A winding It (or It) may be placed around the horizontal portion of one of the sections thus assembled. The various laminations may be bolted together in any approved manner. Thereafter the two complementary assemblies may be dovetailed into each other, the horizontal portions of laminations 30 of one set dovetailing with the horizontal portions of the laminations 30 of the other set. 1

is made of aluminum The ring I! preferably or 18-8 stainless steel or any other non-mags: netic metal. A plurality of copper coils-32, to gether with laminated iron cores 33 within the coils 32, are cast in the ring l1. The coils 32 may have one or arelatively small number of turns. When an alternatingcurrent is passed through the coil IE (or l6), it induces low voltage high ampere current in the coils 32 and heats the same, thusproviding heat for cooking purposes.

The coils 32 extend for some distance around the circumference of ring II, as indicated in Figs. 2 and 7. By turning the ring ll, using handle 2|, the coils 32 may be moved more or less into m the nagneticfiux created in the cores l3 and I4. Asa result, the heat intensity created in the coils 32 may be varied gradually in this manner.

. It is to be noted that the magnetic lines between thepoles' of the magnetic cores may pass.

through the coil varied by'turning the ring it The number of magnetic cores around the circumference of the ringv I! may be one or more, and alarger ,number' than the two (shown in Fig. 2) may be used in order to distribute the heat more evenly -around the circumference ofthe heating unit. Where words such as ring," circumference, etc., are used they are not to be construed strictly Any shape utilizing purview of .these words. By this construction it is possible to vary gradually the intensity of heat imparted to the heat-- ing unit as distinguished from the-stepby step graduations necessary with resistance units commonly used.

The switches l2 may be used to connect the partially, depending on the rotation of the .ring I! about the vertical axis..

enables the intensity of the induced currents- 2,388,286 theutensilhandleistobe While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming claims which follow.

What is claimed is as follows: 1. An electric heating unit comprising a plurality ofU-shaped magnetic cores and primary windings circumferentially arranged with their poles on opposite sides of a circumferential zone, a heating ring in said zone with varying capacities for induced current along its circumference, and means for turning said heating ring to place different portion of itscircumference between said poles.

2. A heating unit for an electric range comprising a plurality of U-shaped magnetic cores and primary windings circumferentially arranged primary windings l5 and It with any type 01' alternating current. If desired the switches l2 may 7 onstructed selectively to connect the windings II and I6 1 across lines of diflerent voltages. Thus in one position of the switches ii, the primary windings may be placed-across 110 volts, in another position across 220 volts and in a third position theiwindings may be disconnected entirely from the source of power. Thus the switch .12 may'con'nect the primary winding across the lines L-Nbr'iL-L, crown the circuitjas indiwith their poles on opposite sides of a circumferential zone, a heating ring in said zone with rings of conducting material and of a relatively small number, of turns along its circumference, and means for turning said heating ring to place more or less of said rings of conducting material between said poles.

3. A heating unit for an electric range comprising a plurality of U-shaped magnetic cores and primary windings circumferentially arranged with their poles on opposite sides of a circumferential zone, a heating ring in said zone with varying capacities for induced current along its circumference, a flat supporting ring along the edge of said heating ring, and means for turning said heating ring to place different portions of its circumference between said poles.

4. (A heating unit comprising a plurality of U-shaped magnetic cores and primary windings circumferentially arranged with their poles on opposite sides of-a circumferential'zone, a heating ring in said zone with rings of conducting material along its circumference, and means for turning said heating ring to place more or less of said rings of conducting poles.

- 5. A heating unit for an electric range comprisinga plurality of U-shaped magnetic cores and primary windings circumferentially arranged material between said ,with their poles on opposite sides of a circumferential zone, a heating ring in-said zone with ,varying capacities for induced current along its to different sources of circumference, means for turning said heating ring to place different portions of its circumference between said poles, and switch means adapted selectively to connect said primary windings alternating current. 6. A heatingunit for an electric range comprising a U-shaped magnetic coreand primary winding arranged with their magnetic poles on opposite sides of a circumferential zone, a heat- 'said ooo k'inrtoliwith a depending heating ring 'in' said acne with varying capacities for induced 1 "current along the circumrerenceand means for within the scope of the essence turning said heating ring to place different portions of its circumference between said poles 8. A heating unit adapted to be placed adjacent the cooking top of an electric range comprising a plurality of U-shaped magnetic cores and primary windings adapted to be arranged below said cooking top with their magnetic poles on opposite sides of a circumferential zone, a plate to be heated adapted to rest along the upper face of said cooking top with a depending heating ring in said zone with varying capacities for induced current along its circumference, and means for turning said heating ring to place different portions of its circumference between said poles.

9. A heating unit adapted to be placed adjacent the cooking top of an electric range comprising a plurality of U-shaped magnetic cores and primary windings adapted to be arranged below said cooking top circumferentially arranged with their poles on opposite sides of a circumierential zone, a plate to be heated adapt d to rest along the upper face of said cooking top with 2, depending heating ring in said zone with rings of conducting material and of a relatively small number of turns along its circumference, and means for turning said ring to place more or less of said rings of conducting material between said poles.

10. An electric heating unit comprising a transformer with a primary winding and a magnetic core structure, a rotatable ring containing in a limited portion thereof the secondary circuit of said transformer structure, said primary winding and magnetic core structure being localized with respect to said ring to provide a localized magnetic field, said rotatable ring being rotatable with respect to said primary winding to vary the relationship between the primary winding and the secondary circuit so as to vary the intensity of the heat produced within the ring, said ring being provided with a surface for supporting in good thermal contact a cooking utensil.

11. An electric heating unit comprising a transformer with a primary winding, a magnetic core structure and a secondary circuit member forming a part or the unit structure, said secondary circuit member being formed to present a surface for supporting and making good thermal surface contact with cooking utensils, and means for laterally moving portions oi the secondary circuit member relative to the primary winding for varying the intensity of heat produced in the secondary circuit member, said primary winding and magnetic core structure being localized with respect to said secondary member to provide a localized magnetic field, a limited portion of said secondary member being 'provided with a local secondary circuit so as to vary the intensity of the heat produced in the secondary member according to relative positions of the localized magnetic field and the local secondary circuit.

12. An electric heating unit comprising a transformer including a plurality of primary windings and magnetic core structures arranged in a plurality of separate zones to provide a plurality of localized magnetic fields, a rotatable secondary circuit member having a plurality of local secondary circuits each located in a difierent zone, and means for turning said secondary circuit member to place said secondary circuits in various relationships to said localized magnetic fields.

13. A heating unit comprising a magnetic core and primary winding arranged with their magnetic poles on opposite sides of a circumferential zone, a heating ring in said zone having sections of various capacities for induced current along its circumference, and means for producing relative movement between said core and said heating ring to place diiierent portions of its circumierence between said poles so as to vary the bean ing of said ring.

1%. A heating unit for an electric range comprising a magnetic core and primary winding arranged with .their magnetic poles on opposite sides of a circumferential zone, a heating ring in said zone having sections of various capacities for induced current along its circumference, and means for producing, relative movement between said core and said heating ring to place different portions of its circumference between said poles so as to-vary the heating of said ring.

15. An electric hot plate heating unit comprising a transformer including a plurality of primary wind ngs and magnetic core structures arranged in a plurality of separate zones to pro-- vide a plurality of localized magnetic fields, a heating element in the form of a laterally movable secondary circuit member having a plurality of local secondary circuits each located in a dif ferent zone, and means for laterally moving said secondary circuit member to place said secondary circuits in various current inducing relationships to said localized magnetic field so as to vary the mt generated in said heating element by said induced current.

DQNAL'D K. PEER-IS. 

